Screening of Suitable Size/Pore Dependent IL/UiO-66 Composite for Selective Gas Separation Application

Abstract

The separation of toxic gases is the imperative environmental demand for which the isostructural UiO-66 metal-organic framework (MOF) has captivated, due to its exceptional thermal and chemical stability. There are two types of pores, the larger octahedral (Oh) pore (i.e., ~16 Å) and the smaller tetrahedral (Td) pore (i.e., ~10 Å), and they both perform differently in adsorbing the gas molecules. To enhance the gas separation application, green solvent ionic liquids (IL) are impregnated. The enormous application lies in its cation-anion tunability. Our interest is to find the most suitable pore for IL occupancy in UiO-66 for effectual CO2 separation. To comprehend the IL interaction inside the pores, [BMIM]+[X]- and [EMIM]+[X]- (Where X = Cl, BF4, PF6, HCOO, and CF3COO) in Oh and Td pores of UiO-66 are studied using the first principle approach. We observe the selectivity and adsorption of composites for selecting the suitable composite for gas separation application. Among the high BE composites, we found [BMIM][PF6]Oh@UiO-66 shows promising selectivity and adsorption.